Here are the essential concepts you must grasp in order to answer the question correctly.
Kiliani–Fischer Synthesis
The Kiliani–Fischer synthesis is a method for elongating the carbon chain of aldoses, allowing the formation of new aldoses from existing ones. This reaction involves the addition of a cyanide ion to the carbonyl group of an aldose, followed by hydrolysis to yield a new aldose with one additional carbon atom. Understanding this process is crucial for analyzing the formation of d-xylose and d-lyxose from d-threose.
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Aldaric Acids
Aldaric acids are a type of dicarboxylic acid derived from aldoses, where both the aldehyde and the primary alcohol groups are oxidized to carboxylic acids. The optical activity of these compounds can vary based on the specific aldose from which they are derived. Recognizing the structural differences between the aldaric acids formed from d-xylose and d-lyxose is essential for understanding their optical properties.
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Optical Activity
Optical activity refers to the ability of a compound to rotate plane-polarized light, a property that arises from the presence of chiral centers in its molecular structure. Compounds that are optically inactive do not rotate light, often due to the presence of a plane of symmetry or the formation of racemic mixtures. In the context of d-xylose and d-lyxose, understanding their optical activity helps in distinguishing their chemical behavior and properties.
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